1. Field of the Invention
The invention relates to an apparatus and process for continuous electrowinning of copper-bearing slurries.
2. State of the Art
Present commercial methods of electrowinning copper to produce a high purity copper product have several drawbacks. Preparatory to electrowinning, an output of a conventional copper ore mill must be placed into solution by appropriate leaching methods, which may require special equipment and conditions. The solution must then be separated from the residual solids and clarified as well as purified of harmful soluble components, especially metal ions other than copper. Subsequently, the solution can be subjected to electrowinning in an electrowinning cell only under conditions allowing use of relatively low current density and requiring recovery of residual copper in the electrolyte leaving the cell. As a result, present methods are equipment and energy intensive.
The present electrowinning methods also fail by producing oxygen at the anode to use the anodic reaction efficiently. The energy expended in the oxidizing of oxygen is lost to the system.
U.S. Pat. No. 3,806,434 discloses an electrowinning cell for electrowinning copper-bearing slurries but does not disclose a leach stage or recovery stage both of which are utilized in the present invention to allow continuous operation. In the cell disclosed a complex mechanical agitation is utilized which is undesirable from a maintenance standpoint.